Solid state storage device with command and control access

ABSTRACT

Several embodiments of memory devices and systems with command and control access are described herein. In one embodiment, a memory device includes a controller having a processor and a memory component operably coupled to the processor. The controller is configured to receive at least one command and control (C 2 ) packet from a remote computer associated with a device vendor. The C 2  packet includes a request for the controller to perform a restricted command, and a vendor signature. The memory component stores instructions executable by the processor to determine if the vendor signature is valid and to direct the controller to perform the restricted command if the vendor signature is determined to be valid.

TECHNICAL FIELD

The disclosed embodiments relate to memory devices and systems. In particular, the disclosed embodiments relate to methods for authorizing and validating a request for a memory device, such as a solid-state drive (SSD), to perform a restricted command.

BACKGROUND

SSDs use non-volatile, solid-state storage media, such as flash media, to persistently store large amounts of data. SSDs can operate in a manner similar to conventional hard disk drives (HDDs), but lack the motor, magnetic disc, read head, and other moving components of HDDs. The lack of moving parts makes SSDs more rugged than HDDs. For example, when an HDD is dropped or shaken, the read head can collide with and sometimes damage the rotating magnetic disc. Additionally, SSDs have faster read/write speeds than HDDs, and they make virtually no noise.

Another advantage of the solid state media of SSDs is that it gives an SSD greater extensibility than an HDD. For example, HDDs typically require a data file to be stored in contiguous memory blocks because the read head needs to read the magnetic media in one continuous motion. By contrast, SSDs can store memory blocks for any one file at arbitrary locations in the solid state media. Additionally, some SSDs can dynamically reduce, or “trim,” memory capacity in exchange for a faster read/write speed.

Some extensible features include restricted commands such as commands for electrically testing the SSD during production or in the field. These commands are typically locked out via password protection to prevent novice or other users from executing them because, in certain cases, the restricted commands may irreversibly alter the SSD and even render it inoperable. For example, some restricted commands can erase or wipe out critical portions of the SSD firmware. One challenge with conventional password protection, however, is that it can be circumvented once a password becomes public knowledge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system having a memory device configured in accordance with an embodiment of the present technology.

FIG. 2 shows a command table containing various restricted commands that can be performed by a memory device in accordance with embodiments of the present technology.

FIG. 3 is a schematic diagram representing a data structure of a command and control packet configured in accordance with an embodiment of the present technology.

FIGS. 4A and 4B are message flow diagrams illustrating various data exchanges with a memory device in accordance with embodiments of the present technology.

FIG. 5 is a flow diagram illustrating a method for operating a memory device in accordance with an embodiment of the present technology.

FIG. 6 is a schematic view of a system that includes a memory device in accordance with embodiments of the present technology.

DETAILED DESCRIPTION

As described in greater detail below, the technology disclosed herein relates to memory devices, systems with memory devices, and related methods for authorizing and validating a request for a memory device to enable or disable a restricted command. A person skilled in the relevant art, however, will understand that the technology may have additional embodiments and that the technology may be practiced without several of the details of the embodiments described below with reference to FIGS. 1-6. In the illustrated embodiments below, the memory devices are described in the context of SSDs incorporating solid-state storage media (e.g., flash storage media). Memory devices configured in accordance with other embodiments of the present technology, however, can include other types of storage media, such as magnetic storage media. For example, a memory device configured in accordance with one embodiment can include an HDD.

FIG. 1 is a block diagram of a system 101 having a memory device or SSD 100 configured in accordance with an embodiment of the present technology. As shown, the SSD 100 includes a main memory component 102 (“main memory 102”) and a memory controller 106 (“controller 106”) operably coupling the main memory 102 to a host device 108 (e.g., an upstream central processor (CPU)) via one or more controller interfaces 104. In some embodiments, the host device 108 and the controller 106 can communicate over a serial interface (e.g., a computer system interface (SCSI), a serial AT attachment (ATA) interface, a peripheral component interconnect express (PCIe) interface, etc.), a test and/or debugging interface, and/or another suitable interface (e.g., a parallel interface). As described in greater detail below, the controller interfaces 104 can further include one or more restricted interfaces (e.g., a joint test action group (JTAG) interface) that can be locked-out to the host device 108 by default.

As further shown in FIG. 1, the main memory 102 includes a plurality of memory units 114 that each include a plurality of memory cells (not shown). The memory cells can include, for example, floating gate, capacitive, ferroelectric, magnetoresitive, and/or other suitable storage elements configured to store a data state persistently or semi-persistently. The main memory 102 and/or the individual memory units 114 can also include other circuit components (not shown), such as multiplexers, decoders, buffers, read/write drivers, address registers, data out/data in registers, etc., for accessing and programming (e.g., reading/writing) memory cells in the main memory 102 and/or performing other commands, such as processing information and/or enabling communication with the controller 106. In one embodiment, each of the memory units 114 can be formed from a semiconductor die and arranged with other memory unit dies in a single device package (not shown). In other embodiments, one or more of the memory units can be co-located on a single die and/or distributed across multiple device packages.

The controller 106 can be a microcontroller, special purpose logic circuitry (e.g., a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.), or other suitable processors. The controller 106 can include a processor 110 configured to execute instructions stored in an internal memory component 112 (e.g., non-volatile memory) to perform various processes, logic flows, and routines for controlling operation of the SSD 100 and managing communications between the SSD 100 and the host device 108. In general, the controller 106 can directly access and program (i.e., read and/or write) the memory units 114. In NAND-based memory units 114, for example, the controller 106 can program selected sub groupings (not shown) of memory cells (known to those skilled in the art as memory pages) and/or larger groupings (not shown) of memory cells (known to those of ordinary skill in the art as memory blocks).

The host device 108 accesses the main memory 102 of the SSD 100 by sending control messages or packets 109 to the controller 106. The control packets 109 typically include a payload field (not shown) containing a request that is to be performed or executed by the controller 106. Such a request can include, for example, a request to program the memory, e.g., a request to program (e.g., read/write) the main memory 102. The payload can also include an address or range of addresses identifying a particular region (e.g., a memory block or memory page) of the main memory 102 to be programmed or otherwise accessed. Typically, the controller 106 can translate these addresses into native memory addresses recognizable by the main memory 102 via, e.g., a flash translation layer. The control packet 109 can also include other fields (not shown), such as a header field, containing information that can include, e.g., host identification, model and/or serial number of the SSD 100, time/date information, a nonce value, and/or other information.

When the controller 106 receives the control packets 109, the controller 106 processes the control packets 109 by, e.g., decapsulating the packets, evaluating certain header information, identifying the requested commands(s) in the packet payload, etc. The controller 106 then performs the commands(s) (e.g., read/write commands) in the packets 109 requested by the host device 108. For example, when the host device 108 requests the controller 106 to read the main memory 102, the controller 106 can read out data from the main memory 102 at a requested memory address. The controller 106 will then return this data to the host device 108 in a return packet (not shown).

In the embodiment illustrated in FIG. 1, the controller 106 is further configured to validate certain types of control packets containing requests to perform enable or disable commands. In some embodiments described below, the enable/disable commands are used to enable or disable restricted commands, such as programming, reading, and/or other memory accessing commands, that are provided by a device vendor 120 for use on the SSD 100. Such restricted commands are referred to, herein, as vendor specific commands, or “VS commands.” The device vendor 120 can include, for example, the manufacturer and/or supplier of the SSD 100 and/or the host device 108 (e.g., an original equipment manufacturer (OEM)), and/or an affiliate (e.g., a 3rd party service) of the manufacturer and/or the supplier. The device vendor 120 can provide or host one or more remote computers (not shown), such as remote servers, for authorizing enable or disable commands over a network and/or other suitable connection 122 (e.g., wired, wireless, point-to-point, public, private, serial, parallel, or other data connections) with the host device 108.

VS commands can differ from standard or generic controller commands (e.g., read/write commands) and can include proprietary, customized, and/or other non-standard commands. For example, some VS commands can enable the host device 108 to access (i.e., via the controller 106) a restricted region 124 of the main memory 102, the internal memory component 112 of the controller 106, and/or a restricted interface of the controller interfaces 104 (e.g., a test interface). Certain VS commands can also enable the host device 108 to program restricted regions of the SSD 100 via the controller 106. For example, in some embodiments, a VS command can enable the host device 108 to load data (e.g., a boot block) into firmware (e.g., into the internal memory component 112 of the controller 106).

The enable/disable commands require authorization from the device vendor 120 before the SSD 100 can perform them. As described below, the device vendor 120 authorizes these enable/disable commands by signing the packets with a vendor authorization signature (not shown). When a packet or other similar message is signed, it is referred to herein as a “command and control” (C²) packet 160. In at least some embodiments, the C² packet 160 is a control packet 109 that includes the vendor signature. As described below, the SSD 100 can include a command table 116 (stored, e.g., in the main memory 102 or in the internal memory component 112, as is shown in the illustrated embodiment) to identify whether a control packet requires a vendor signature. The host device 108 cannot create or append a valid vendor signature to a control packet. Thus, the host device 108 is prevented from carrying out VS commands of the SSD 100 without authorization from the device vendor 120. As further described below, the SSD 100 can validate a vendor signature once it receives a C² packet 160 to prevent the SSD 100 from executing the enable or disable command of a C² packet 160 that has a fraudulent or otherwise invalid authorization signature.

In some embodiments, the device vendor 120 can use the command and control capability of the C² packet 160 to provide extensible, upgradeable, and/or other services to the end user of the SSD 100 and/or the host device 108. For example, the device vendor 120 can send a signed C² packet 160 to the SSD 100 to enable VS commands that will unlock the restricted region 124 and thereby expand the memory capacity of the SSD 100. In one embodiment, the device vendor 120 can allow a customer to purchase the SSD 100 with a reduced maximum memory capacity (e.g., 1 TB), but with an option to expand the maximum memory capacity (to, e.g., 2 TB) through purchase (e.g., Internet purchase). In this example, when the customer completes such a purchase, the device vendor 120 can send a signed C² packet 160 to the customer's SSD 100 to enable VS commands that will unlock the restricted region 124 and thereby expand the capacity of the main memory 102. In certain embodiments, the device vendor 120 can use the command and control capability to give service technicians temporary (e.g., time or boot-cycle limited) access to certain restricted VS commands for testing, debugging, or other servicing of the SSD 100 when deployed in the field. In these and other embodiments, the command and control capability can also prevent unauthorized access to hackers and/or unscrupulous users that attempt to access the restricted VS commands of the SSD 100.

FIG. 2 shows the command table 116 of FIG. 1 containing various commands that can be performed by the SSD 100 (FIG. 1) in accordance with embodiments of the present technology. As shown, the command table 116 includes Standard commands 230, VS commands 231, and Enable/Disable commands 232 that can be performed by the SSD 100. The Standard commands 230 can include, for example, conventional commands S₁-S₃, such as read, write, and erase commands, respectively. The SSD 1000 can perform the Standard 230 commands at the request of the host device 108, and these Standard commands 230 do not need to be enabled by the device vendor 120 (FIG. 1).

The VS commands 231 are vendor specific commands provided by the device vendor 120 that must be first enabled by the device vendor 120 before they can be performed by the SSD 100. In the embodiment illustrated in FIG. 2, the VS commands 231 include a first VS₁ command that enables the host device 108 (FIG. 1) to access (e.g., program) the restricted memory 124 (FIG. 1) of the SSD 100, a second VS₂ command that enables the host device 108 to use a restricted one of the interfaces 104 (FIG. 1) of the SSD 100, and a third VS₃ command that enables the host device 108 to load data (e.g., boot block data) into the internal memory component 112 (FIG. 1) of the SSD 100. In additional or alternate embodiments, the VS commands 231 can include other types of unique, customized, and/or proprietary commands, such as commands for formatting the main memory 102, retrieving restricted data, and/or increasing performance (via, e.g., overclocking) In some of these embodiments, certain VS commands 231 can be enabled by purchase via, e.g., an Internet service. In the embodiment illustrated in FIG. 2, the VS commands 231 can have an associated status indicator 234 that indicates whether a particular VS command is enabled or disabled on the SSD 100.

The Enable/Disable commands 232 are commands performed by the SSD 100 to enable/disable VS commands 231 for use on the SSD 100. For example, in the embodiment illustrated in FIG. 2, the Enable/Disable commands 232 can include an enable E₁ command that collectively enables all of the VS commands 231; a temporary enable E₂ command that temporarily enables the VS commands 231 for only a limited duration (e.g., a certain number of minutes, hours, days, weeks, months, boot cycles, etc.); and a disable D₁ command that collectively disables the VS commands 231. In additional or alternate embodiments, the Enable/Disable commands 232 can include commands that enable and/or disable VS commands 231 individually and/or in collective subsets of VS commands 231. As described below, the Enable/Disable commands 232 can be contained in the payload field of the C² packet 160 (FIG. 1).

FIG. 3 is a schematic diagram of a data structure representing the C² packet 160 of FIG. 1 in accordance with embodiments of the present technology. In the embodiment illustrated in FIG. 3, the C² packet 160 contains multiple fields, including a header field 362, a payload field 364, and a signature field 366. The header field 362 can include information that identifies the target SSD 100 (FIG. 1) from or to which the C² packet 160 is being received or sent, respectively. For example, the header field 362 can include a Drive Serial number, a Drive Lot number, a Manufacturer ID, a public key, a nonce value, and/or other identifying information (not shown). A nonce value can be used by the SSD 100 to thwart any attempts by the host device 108 (FIG. 1) or other device to circumvent authorization and/or validation by replaying a previous packet transmission. In general, the nonce value is incremented from its previous or original value each time the packet is transmitted, which enables the SSD 100 to detect whether a packet is an original transmission or merely a re-played transmission. The payload field 364 can include, for example, the Enable/Disable Command 232 (FIG. 2) requested by the host device 108, the VS command 231 (FIG. 2) to be enabled/disabled, one or more target memory addresses (not shown), and/or other information. In some embodiments, the payload field 364 can be encoded (e.g., encrypted).

The signature field 366 is configured to contain the vendor signature 368 of the device vendor 120 (FIG. 1) when the device vendor signs the C2 packet 160. In some embodiments, the device vendor derives the vendor signature 368 by first computing a digest (e.g., a hash code) based on information contained in the C2 packet 160, such as information stored across the payload field and/or the header field. The device vendor then encodes (e.g., encrypts) this digest to produce a unique code. In such embodiments, this unique code is the vendor signature.

FIGS. 4A and 4B are message flow diagrams illustrating various data exchanges with the SSD 100 of FIG. 1 in accordance with embodiments of the present technology. FIG. 4A shows a series of first message flows between the host device 108 and the SSD 100. In particular, FIG. 4A shows a control packet 409 sent from the host device 108 to the SSD 100 requesting the SSD 100 to perform the first VS₁ command. As shown in the command table 116 of FIG. 2, the first VS₁ command is currently disabled. Accordingly, when the SSD 100 receives the control packet 409, it will deny the request to perform the first VS₁ command. In such cases, the SSD 100 can send a response 411 (e.g., a response packet) to the host device 108 indicating that the request to perform the first VS₁ command was denied.

FIG. 4B shows a series of message flows between the host device 108, the SSD 100, and the device vendor 120 for authorizing the first VS₁ command denied by the SSD 100 in FIG. 4A. In the illustrated embodiment, the host device 108 creates an unsigned version of a C² packet 460 a. This C² packet 460 a can include, for example, the information in the header field 362 and the payload field 364 discussed above with reference to FIG. 3. However, the unsigned C² packet 460 a does not include a vendor signature 368 (FIG. 3) in the signature field 366 (FIG. 3). For example, the signature field 366 can include a blank or null value. In the embodiment illustrated in FIG. 4B, the payload field 364 includes the enable E₁ command (FIG. 2) for enabling all of the VS commands 231 (FIG. 2) of the SSD 100. In other embodiments, however, the payload field 364 can include other types of enable commands, such as the temporary enable E₂ command to temporarily enable one or more of the VS commands 231. Further, in other embodiments, the host device 108 can request that one or more of the VS commands 231 be disabled via, e.g., the disable D₁ command (FIG. 2). Once the host device 108 creates the unsigned C² packet 460 a, it can send the C² packet 460 a to the device vendor 120 for authorization. For example, in one embodiment, the host device 108 can encapsulate the C² packet 460 a in an IP packet 461 that it can send to the device vendor 120 over an IP network (not shown).

When the device vendor 120 receives the unsigned C² packet 460 a from the host device 108, it first determines whether the enable E₁ command is authorized for use on the SSD 100. In some embodiments, authorization can be based on affinity and/or a unique identification associated with the SSD 100, such as the drive serial number, the public key, and/or the model number contained in the header field 362 of the unsigned C² packet 460 a. If authorization is to be granted, the device vendor 120 signs the unsigned C² packet 460 a to produce a signed C² packet 460 b having a vendor signature 368 in the signature field 366 of the packet 460 b. The device vendor 120 then sends the signed C² packet 460 b to the SSD 100 via the host device 108, such as via an encapsulated IP packet 462. If authorization is not granted, however, the device vendor 120 can send a response to the host device 108 indicating that the authorization was denied.

Upon receiving the signed C² packet 460 b, the SSD 100 determines whether the vendor signature 368 is valid. If the SSD 100 determines that the vendor signature 368 is, in fact, valid, the SSD 100 will enable the VS commands 231 of the SSD 100. When the VS commands 231 are enabled, the host device 108 can send VS commands 231 directly to the SSD 100 without requiring further device vendor authorization. For example, as further shown in FIG. 4B, the host device 108 can subsequently request the SSD 100 to perform the first VS _(I) command previously denied by the SSD 100 in FIG. 4A by resending control packet 409 (FIG. 4A) to the SSD 100.

FIG. 5 is a flow diagram illustrating a routine 570 for operating a memory device in accordance with an embodiment of the present technology. In one embodiment, the routine 570 can be executed by a combination of the SSD 100 (FIG. 1), the host device 108 (FIG. 1), and/or the device vendor 120 (FIG. 1). The routine 570 begins by receiving an unsigned C² packet at the device vendor 120 containing a request to perform a restricted command (block 571), such as a request to perform one of the Enable/Disable commands 232 shown in FIG. 2. For example, the routine 570 can begin after the host device 108 creates the unsigned C² packet 460 a (FIG. 4B) and sends this packet to the device vendor 120.

The routine 570 next determines whether to authorize the authorize the C2 packet for use at the SSD 100 (block 572). In some embodiments, the routine 570 determines whether to process the C2 packet based on affinity and/or unique identification associated with the SSD 100, such as the drive serial number, the public key, and/or model number contained in the header field of the unsigned C2 packet. In these and other embodiments, permission can be granted in combination with the SSD 100 identity and the identity of the host device 108, user credentials (e.g., a user ID and password), and/or the particular command requested to be enabled. In some instances, credentials, affinity, and/or other information regarding the host device 108 and/or the SSD 100 can be looked up in a database and compared to information contained in the unsigned C2 packet. If the routine 570 determines that authorization should be granted, the routine will ultimately sign the C2 packet with a vendor signature, as described below. If authorization is not granted, however, the routine 570 can send a response to the host device 108 and/or the SSD 100 indicating that the request was denied.

In one aspect of the various embodiments of the present technology, the device vendor 120 derives the vender authorization signature by creating a first digest based on information contained in the unsigned C2 packet (block 573), such as information contained in the header field and/or the payload field of the unsigned packet. The first digest can include, for example, a hash code derived using a hash table and/or hash function. The routine 570 then encodes (e.g., encrypts) the first digest using, e.g., a hardware security module (HSM), or other suitable cryptographic processor, to produce a unique code (block 574). In some embodiments, an HSM can hold private/public key pairings, such as private/public key pairings associated with a Rivest-Shamir-Adleman (RSA) algorithm. In other embodiments, the HSM can encode the first digest using other suitable digital signature algorithms, such as a symmetric encryption algorithm. The routine 570 then sends the signed C2 packet to the SSD 100 via the host device 108 (block 575), with the unique code serving as the vendor signature.

The routine 570 next receives the signed C2 packet at the SSD 100 (block 576), and proceeds to determine whether the vendor signature of the signed C2 packet is valid (blocks 577 and 578). In the illustrated embodiment of FIG. 5, the routine 570 determines whether the vendor signature is valid by deriving a second digest (e.g., a hash code) from the information contained in the signed C2 packet (block 577). In particular, the routine 570 can create the second digest based on the same information used to produce the first digest at block 573 (e.g., credentials in the header field and/or the restricted command in the payload field). The routine 570 also decodes (e.g., decrypts) the vendor signature (i.e., the unique code) of the C2 packet using an algorithm (e.g. an RSA algorithm) to produce a third digest (block 578). In cases where a public/private key pairing is employed for encoding/decoding (e.g., encrypting/decrypting), the routine 570 can decode the vendor signature using a public key stored, e.g., in the internal memory 112 (FIG. 1) and/or the main memory 102 (FIG. 1) of the SSD 100. The public key stored on the SSD 100 can be different than the public key supplied by the host device 108 in the header field of the C2 packet or it can be the same.

If the derived second digest is equivalent to the third digest (i.e., the decoded vendor signature), the routine 570 can recognize that the C2 packet is valid (block 579). If the derived second digest is not equivalent to the decoded vendor signature, however, the vendor signature cannot be validated and the routine 570 can deny the request. In some embodiments, once the vendor signature is validated, the routine 570 can check other packet parameters to ensure the signed C2 packet is not corrupted. For example, the SSD 100 can check any credentials contained in the header field of the signed C2 packet to, e.g., ensure that the packet was sent to the correct SSD. If the parameters or credentials are invalid or otherwise unacceptable, the SSD 100 can also deny the request. Otherwise, the SSD 100 can proceed to perform the restricted command of the C2 packet (block 580).

FIG. 6 is a schematic view of a system that includes a memory device in accordance with embodiments of the present technology. Any one of the foregoing memory devices described above with reference to FIGS. 1-5 can be incorporated into any of a myriad of larger and/or more complex systems, a representative example of which is system 680 shown schematically in FIG. 6. The system 680 can include a memory device 600, a power source 682, a driver 684, a processor 686, and/or other subsystems or components 688. The memory device 600 can include features generally similar to those of the memory devices described above with reference to FIGS. 1-5, and can, therefore, include various features that provide command and control access to the memory device. The resulting system 680 can perform any of a wide variety of commands, such as memory storage, data processing, and/or other suitable commands. Accordingly, representative systems 680 can include, without limitation, hand-held devices (e.g., mobile phones, tablets, digital readers, and digital audio players), computers, vehicles, appliances and other products. Components of the system 680 may be housed in a single unit or distributed over multiple, interconnected units (e.g., through a communications network). The components of the system 680 can also include remote devices and any of a wide variety of computer readable media.

From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the disclosure. In addition, certain aspects of the new technology described in the context of particular embodiments may also be combined or eliminated in other embodiments. Moreover, although advantages associated with certain embodiments of the new technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein. 

I/we claim:
 1. A memory device comprising a controller, wherein the controller includes a processor and a memory component operably coupled to the processor, and wherein: the controller is configured to receive a command and control (C²) packet from a remote computer associated with a device vendor, the C² packet including— a request for the controller to perform a restricted command, and a vendor signature; and the memory component stores instructions executable by the processor to— determine if the vendor signature is valid, and direct the controller to perform the restricted command if the vendor signature is determined to be valid.
 2. The memory device of claim 1 wherein: the vendor signature includes a first digest of the C² packet that has been encoded based on a private key held by a device vendor; and the instructions are executable by the processor to— derive a second digest based at least in part on information stored in the C² packet; decode the vendor signature with a public key associated with the private key to produce a third digest, and compare the third digest to the second digest to determine if the vendor signature is valid.
 3. The memory device of claim 2 wherein the first, second, and third digests each include a hash code.
 4. The memory device of claim 1 wherein the C² packet includes: a first field including the restricted command; and a second field including the vendor signature.
 5. The memory device of claim 1 wherein the device vendor is a manufacturer of the memory device.
 6. The memory device of claim 1 wherein the controller is configured to receive the C² packet from a remote computer hosted by the device vendor via a host device operably coupled to the controller.
 7. The memory device of claim 1 wherein the memory device is a solid-state drive.
 8. A method of operating a memory device, comprising: receiving at least one command and control (C²) packet from a remote computer associated with a device vendor, wherein the at least one C² packet includes a restricted command that has been disabled on the memory device; determining whether the at least one C² packet has been signed by the device vendor with a vendor signature; and performing the restricted command if the vendor signature is valid.
 9. The method of claim 8 wherein determining whether the at least one C² packet has been signed by the device vendor includes: deriving a first digest from the at least one C² packet; decoding the vendor signature to produce a second digest, wherein decoding the vendor signature includes using an algorithm implementing a public key associated with a private key held by the device vendor; and comparing the first digest to the second digest.
 10. The method of claim 9 wherein the first digest includes a hash code.
 11. The method of claim 8 wherein the restricted command includes an enable command configured to enable one or more vendor specific commands that are disabled on the memory device, and wherein the method further comprises: determining that the at least one C² packet has been signed by the device vendor; performing the restricted command of the at least one C² packet to enable the one or more vendor specific commands; and after performing the restricted command— receiving a control packet from a host device that includes at least one of the vendor specific commands; and performing the at least one of the vendor specific commands.
 12. The method of claim 11 wherein: the memory device includes a solid-state drive (SSD) having a memory storage component with a restricted region; and performing the at least one of the vendor specific commands includes allowing the host device to access the restricted region of memory.
 13. The method of claim 11 wherein: the memory device includes a solid-state drive (SSD) having a memory storage component with a restricted interface; and performing the at least one of the vendor specific commands includes allowing the host device to access the memory storage component using the restricted interface.
 14. The method of claim 11 wherein receiving the at least one C² packet includes receiving the C² packet from a remote computer hosted by the device vendor via the host device.
 15. A method for providing command and control access to a memory device, the method comprising, receiving an unsigned command and control (C²) packet from a host device operably coupled to the memory device, wherein the C² packet includes a restricted command requested by the host device to be performed on the memory device; determining whether the memory device is authorized to perform the restricted command of the C² packet; and if the memory device is authorized to perform the restricted command— signing the unsigned C² packet with a vendor signature to produce a signed C² packet, and sending the signed C² packet to the memory device via the host device.
 16. The method of claim 15 wherein signing the C² packet includes appending a vendor signature to the C² packet.
 17. The method of claim 15 wherein signing the C² packet includes: producing a digest based on information stored in the C² packet encoding the digest based on a private key held by the device vendor and associated with a public key held by the memory device; and appending the digest to the unsigned C² packet.
 18. The method of claim 15 wherein determining whether the memory device is authorized to perform the restricted command of the unsigned C² packet includes identifying the memory device based on information stored in a header field of the unsigned C² packet.
 19. The method of claim 18 wherein the information stored in the header field of the unsigned C² packet includes at least one of a serial number and a model number associated with the memory device.
 20. The method of claim 15 wherein memory device is a solid-state drive (SSD). 